Pipe coupling

ABSTRACT

A pipe coupling for connection of a pair of longitudinally spaced pipe ends without rotation of either of the pipes connected by the well heads with service facilities at the surface or along the ocean floor. The coupling may also connect pipe members to provide a leakproof union allowing rotation of one pipe relative to the other. The coupling includes a first outer pipe section having inner threads and a second inner pipe section having external threads, at least one of such threads being tapered. The pipe sections are joined together by a threaded gland having inner threads mating with the threads on the inner pipe section and external threads mating with the inner threads on the outer pipe section. The gland has an extension projecting over the inner pipe section from the overlapping portions of the two pipe sections for engagement of a tool to turn the gland. One of the threaded connections with the gland stresses the gland sufficiently to tighten the other threaded connection with the gland. One form of coupling employing the invention comprises an extension joint for connecting spaced pipe ends. Another pipe joint embodying the invention permits two pipe sections to be aligned and the connection between them tightened by the gland without rotation of the sections themselves. Additional specific applications of the coupling shown comprise multiple section articulated pipe assemblies which are readily deformable to provide turns both within a given plane and between different planes in a universal joint type manner. The articulated pipe assemblies are especially suited to connection of underwater wee heads with service facilities at the surface or along the ocean floor. Additional specific applicatins of th coupling shwwn comprise multiple section articulated pipe assemblies which are readily deformable to provide turns both within a given plane and between different planes in a universal join type manner. The articulated pipe assemblies are especially suited to connection of underwater well heads with service facilities at the surface or along the ocean floor.

[ Dec. 11, 1973 PIPE COUPLING v [75] Inventors: John V. Fredd, Dallas,Tex.

[73] Assignee: Otis Engineering Corporation, Dallas, Tex.

22 Filed: Mar. 22, 1971 211 Appl. No.: 126,539

[52] US. Cl 285/39, 285/94, 285/137 A, 285/169, 285/332.3, 285/357,285/392 [51] Int. Cl. F161 39/04 [58] Field of Search 285/357, 32, 323,.2 .3. .Z. 39, 94 6.81162 332- [56] References Cited UNITED STATESPATENTS 2,210,826 8/1940 Williams 285/94 426,922 4/1890 Cook 285/94 X1,372,876 3/1921 Freund.... 285/357 426,922 4/1890 Cook 285/94 X1,707,087 3/1929 Little 285/357 X 1,517,893 12/1924 Elder 285/322,631,871 3/1953 Stone 285/106 1,517,893 12/1924 Elder 285/32 2,457,64812/1948 Donner 285/323 1,822,887 9/1931 l-lagstedt 285/357 PrimaryExaminerThomas F. Callaghan Att0mey-H. Mathews Garland [57] ABSTRACT Apipe coupling for connection of a pair of longitudinally spaced pipeends without rotation of either of the pipes connected by the well headswith service faleakproof union allowing rotation of one pipe relative tothe other. The coupling includes a first outer pipe section having innerthreads and a second inner pipe section having external threads, atleast one of such threads being tapered. The pipe sections are joinedtogether by a threaded gland having inner threads mating with thethreads on the inner pipe section and external threads mating with theinner threads on the outer pipe section. The gland has an extensionprojecting over the inner pipe section from the overlapping portions ofthe two pipe sections for engagement of a tool to turn the gland. One ofthe threaded connections with the gland stresses the gland sufficientlyto tighten the other threaded connection with the gland. One form ofcoupling employing the invention comprises an extension joint forconnecting spaced pipe ends. Another pipe joint embodying the inventionpermits two pipe sections to be aligned and the connection between themtightened by the gland without rotation of the sections themselves.Additional specific applications of the coupling shown comprise multiplesection articulated pipe assemblies which are readily deformable toprovide turns both within a given plane and between different planes ina universal joint type manner. The articulated pipe assemblies areespecially suited to connection of underwater wee heads with servicefacilities at the surface or along the ocean floor. Additional specificapplicatins of th coupling shwwn comprise multiple section articulatedpipe assemblies which are readily deformable to provide turns bothwithin a given plane and between different planes in a universal jointype manner. The articulated pipe assemblies are especially suited toconnection of underwater well heads with service facilities at thesurface or along the ocean floor.

PATENTEUUEC 1 1 ma INVENTOR. J o h n V. Fr e d d BY HNMNXM ATTORNEYPMENIEDnEc 1 I I973 3.778.089 SHEET 20F 5 INVENTOR. J o h n V. F re d dATTORNEY SHEET 3 [1F 5 PATENTEU DEC 1 1 I975 INVENTOR. Joh n V. Fre ddATTORNEY PATENTED HEM 1 I973 SHEET t 0F 5 INVENTOR. J oh n V. F re d dATTORNEY mn mgnnzc n 1915 3.778.089 sum 5 m 5 A42 INVENTOR John V. FreddBY Wk M ATTORNEY Fig.9

PIPE COUPLING This invention relates to pipe couplings and moreparticularly relates to couplings for interconnection of a pair ofthreaded members.

It is a particularly important object of the imvention to provide a newand improved coupling for threaded members.

It is another object of the invention to provide a pipe coupling whichforms an extension joint assembly for interconnection of spaced pipeends without rotation of either of such pipe ends.

It is another object of the invention to provide a pipe extension jointassembly which is adjustable in length without affecting the fluid-tightintegrity of the threaded connections.

It is another object of the invention to provide a longitudinallyadjustable pipe coupling which does not require gaskets for sealingagainst leakage.

It is another object of the invention to provide a pipe coupling whichincludes a leakproof straight threaded connection permittinglongitudinal adjustment of the coupling.

' It is another object of the invention to provide a pipe coupling whichhas first and second pipe members interconnected by an internally andexternally threaded gland.

It is another object of the invention to provide a pipe coupling whichmay be tightened by turning a connecting gland while holding theconnected pipe sections against rotation.

It is another object of the invention to provide a gland secured pipecoupling wherein the gland is secured by a straight threaded connectionto one pipe and a tapered threaded connection to the other pipe.

It is another object of the invention to provide a pipe coupling of thecharacter described which includes a connecting gland having internaland external threads tapered at different angles.

It is another object of the invention to provide a pipe coupling inwhich threaded ends of two pipe sections are interconnected by aninternally and externally threaded gland which is rotatable along one ofthe pipe sections to permit adjustment of the length of the couplingbetween the sections and/or changes in the relative positions oralignment of the connected pipe sections.

It is another object of the invention to provide an articulated pipeassembly which is readily deformable from a straight line configurationto a multiplicity of curved arrangements dependent upon the number ofsections making up the assembly and the degree of direction change ateach coupling in the assembly.

It is another object of the invention to provide an articulated pipeassembly having a plurality of sections, each of which comprises several.generally parallel pipe sections which are connected at opposite endsto other pipe sections by couplings in accordance with the invention todefine a desired number of separate flow passages along the length ofthe pipe assembly.

It is another object of the invention to provide an articulated pipeassembly which is adjustable between various shapes to permit connectionof a well head between well servicing equipment either at a locationgenerally at the same elevation of the well head, with equipmentvertically disposed over the well head, or with equipment at anylocation between the same elevation or vertically above the well head.

It is another object of the invention to provide an articulated pipeassembly which permits the shaping of the assembly from a straight to anumber of curved configurations while maintaining the flow passage orpassages through the assembly at curvatures which allow movement ofpumpable tools along the flow passages throughout the lengths of thepipe assemblies.

These and other objects of the invention will be apparent from readingthe following description of apparatus embodying the invention taken inconjunction with the accompanying drawings wherein:

FIGS. I-A and 1-H taken together constitute a longitudinal view insection of an extensible pipe coupling embodying the inventionpositioned to connect spaced ends of a pair of pipe sections;

FIG. 2 is a view partially in elevation and partially in section of oneform of articulated pipe assembly utilizing a coupling embodying theinvention;

FIG. 3 is an enlarged view in elevation showing an end of one of thecoupling'bodies of the assembly of FIG. 2 and end portions of the curvedpipe sections connected into the body;

FIG. 4 is a view in section along the line 44 of FIG. 3 showing the useof the pipe couplings embodying the invention for connecting pipesections into opposite ends of the coupling body of one of the couplingsused in the assembly of FIG. 2;

FIG. 5 is a view in section of another form of articulated pipe assemblyemploying pipe couplings embodying the invention with the assemblyarranged in a curved shape;

FIG. 6 is a view partially in section and partially in elevation of theportion of the pipe assembly shown in FIG. 5 straightened so that theinterconnected pipe sections generally extend along a straightlongitudinal axis;

FIG. 7 is a view in elevation of an articulated pipe assembly using pipesections of the type represented in FIGS. 5 and 6 with the assemblyarranged along a curved axis to traverse a substantially change ofdirection;

FIG. 8 is a broken longitudinal view in elevation of the assembly ofFIG. 7 straightened to extend along a straight longitudinal axis;

FIG. 9 is a view partially in section and partially in elevation of analternate form of gland having straight inner threads and both taperedand straight outer threads;

FIG. 10 is a fragmentary longitudinal half section of a couplingembodying the invention including a gland having tapered inner and outerthreads; and

FIG. 11 is a fragmentary view in section and elevation of a couplingembodying the invention wherein the connected sections are aligned andtightening is effected by the gland.

'In accordance with the principal feature of the invention there isprovided a pipe coupling which forms a rotatable joint for connection ofpipe ends. The coupling includes a first pipe section having taperedinternal threads, a second pipe section telescopically disposed withinthe first pipe section and having external straight threads, and aninterconnecting gland threaded between the first and second pipesections provided with external tapered threads and internal straightthreads. The gland has an exposed portion exterior of the overlap of thejoined pipe sections to permit a wrench or other pipe tool to engage thegland for rotating it. The wedging effect of the mating tapered threadson the first pipe section and gland squeezes the gland radially inwardlyto aid in effecting a seal along the mating straight threads of thegland and the second pipe section. The second pipe section is rotatablein the gland along the straight threads for adjustment of its positionrelative to the first pipe section while maintaining a fluid-tight sealeffected along the straight threads. The coupling is useful as anextension joint for connecting spaced pipe ends. The coupling is alsouseful to form an articulated pipe assembly utilizing spaced connectorbodies, each having separate laterally spaced, longitudinally extendingbores provided at opposite ends with internal tapered threads into eachof which is secured a gland having external tapered threads and internalstraight threads. The glands threaded into the opposite ends of each ofthe bores are each connected with a curved pipe section. Several suchclusters or bundles of curved pipe sections and connector bodies areinterconnected to provide the articulated assembly. In another form ofarticulated pipe assembly using the pipe coupling of the invention,single sections of pipe of slight curvature are interconnected insufficient number to permit shaping of the articulated assembly todesired degrees of curvature from a straight arrangement to a curve,such as 90, depending upon the number of sections employed. In a furtherform of the invention pipe sections are connected by a gland havinginner and outer threads of different tapers whereby gland rotationtightens a coupling without rotating the connected pipe sections.

Referring to FIGS. l-A and l-B of the drawings, spaced pipes and 11 areconnectible together by an extensible coupling 12 constructed inaccordance with the invention without rotation of either of theconnected pipes. The extensible coupling includes a first outer pipesection 13, a second telescopically disposed inner pipe section 14, anda connecting gland 15 which adjustably secures the first and second pipesections together. The first pipe section 13 is provided with a threadwhich is tapered outwardly toward the open end of the pipe sectionadjacent the gland 15. The tapered thread 20 mates with an externaltapered thread 21 on the gland 15. The gland 15 has an internal straightthread 22 which extends along the gland a slightly greater distance thanthe external thread 21 and mates with an external straight thread 23formed along a substantial portion of the length of the inner pipesection 14. The gland has an extended, slightly enlarged collar portion24 which has any suitable external surface finish or shape, such as amulti-faceted surface or a knurled surface, to facilitate engagement ofthe collar portion by a tool, such as a wrench, for turning the gland.The threaded end portion of the gland having the threads 21 is providedwith a hole 25 in which a ball member, such as a nylon ball 26, isinserted prior to connection of the two pipe sections by the gland. Asthe coupling parts are screwed together, the nylon ball is squeezedbetween the straight external threads 23 of the inner pipe section andthe internal tapered threads 20 of the external pipe sections to enhancethe seal between the threads of the gland and both of the pipe sections.

The internal gland thread 22 extends into the gland to a smooth boreportion 27 which extends to an internal bore end portion having threads22a. The threads 22a are of the same form and dimensions as the thread22 with, however, the thread crests cut off. The gland bore surface 27with the thread surfaces 23 encompassed by the surface 27 defines anannular grease chamber 28 within the gland. A lateral bore 29 is formedin the gland opening into the annulus 28 for a grease fitting, notshown, through which grease is injected for lubricating the threadsbetween the gland and the pipe 14. The threads 23 on the pipe 14terminate a short distance from an external shoulder 14a providing ashort, smooth surface 14b along the pipe between the threads 23 and theshoulder. The surface 14b is provided due to manufacturing difficultiesof running the threads all the way against the shoulder. The threads 22aprovide an internal bearing surface in the gland for gland support tocompensate for a wrench on the end portion of the gland when turning thegland on the pipe 14 along the threads 23. The shoulder 14a when engagedby the end surface 240 of the gland at the position of FIG. l-B preventsgrease leakage as grease is forced into the annulus 28 before threadingthe gland away from the shoulder on the pipe 14.

The length of engagement along the straight thread portions of the glandand the pipe section 14, as substantially represented between thereference numerals 30 and 31, is a factor in the sealing capability ofthe coupling. Preferably, the character of the surfaces along which thegland threads 22 and pipe threads 23 are formed and the force wedging orurging the threads together, taken in conjunction with the length ofengagement of the threads, presents sufficient resistance to fluid flowbetween the parts along the threads that, under the operating conditionfor which the coupling is designed, no leakage may occur from within thecoupling along the gland. The nylon ball 30 enhances the seal betweenthe threads to impede leakage which might occur spirally along thelength of the gland's grooves defined by the threads. The force withwhich the straight threads are urged together is a direct function ofthe wedging effect of the gland 15 developed by the extent to which itis threaded into the outer pipe section 13 along the threads 20. As thegland is engaged with the threads 20 along the tapered threads 21 of thegland, the further the gland is threaded into the pipe section, the morethe engaged portion of the gland is squeezed radially inwardly aroundthe straight threads 23 of the inner pipe section. It has been foundthat the various factors which affect the sealing capability of thecoupling, including the squeezing effect on the gland of the taperedthreads and the length of engagement of the straight threads of thegland and the inner pipe section, provide a coupling which resistsleakage at substantial operating pressures while remaining capable oflongitudinal adjustment by rotation of the inner pipe section 14relative to the gland 15. After the coupling is made up with the glandthreaded into the outer pipe section to the extent sufficient to providethe desired seal between the gland and the inner pipe section along thestraight threads, the outer pipe section 13 is readily rotatable forpurposes of adjusting the length of the coupling.

In the form of the coupling illustrated in FIGS. l-A and l-B, the outerpipe section 13 is provided with internal tapered threads 31 along anupper end portion of the pipe section for engagement of the pipe sectionwith external tapered threads 32 formed along the lower end portion ofthe pipe section 10. Similarly, the inner pipe section 14 has externaltapered threads 33 formed along a lower end portion for engagement ofthe pipe section with the internal tapered threads 34 formed along anupper end portion of the pipe section 11.

The extension joint of the invention is particularly well suited tofacilitate spacing-out, make-up, and the like, of tubing between twomultiple string packers, such as packers useful with multiple strings inan oil well manufactured and sold by Otis Engineering Corporation. Insuch well arrangements, the coupling 12 is used to interconnect at leasttwo pipe sections extending between two such multiple string packers. Itwill be apparent to those skilled in the art that in connecting such apair of packers together by multiple pipe strings, some type of pipecoupling is necessary for interconnecting sections of the strings aftermake-up of the first string between the packers. Assuming the pipesections and 11 extend to spaced and aligned upper and lower packers andthat the end portions of the pipe sections as shown are a distance apartwithin the length to which the coupling 12 can be extended, suchcoupling may be used to connect the pipe sections.

The coupling may be assembled by first threading the gland onto theinner pipe section 14 until the gland end face 24a engages the shoulder14a on the pipe. As apparent from the previous description of thecomponents of the coupling, the gland is threaded to the pipe section 14by engagement of the straight threads 22 of the gland with the straightthreads 23 of the pipe section. A grease fitting, not shown, isinstalled in the bore 29, and grease is forced into .the gland annulus28 around the threads 23 for lubrication and sealing. The seating of thegland end 24a on the shoulder 14a prevents leakage of the grease alongthe threads 22a during the initial grease injection. A nylon ball 30 isplaced in the hole 25 of the gland and the pipe 13 is threaded on thegland. The tapered internal threads 20 of the outer pipe section areengaged with the external tapered threads 21 of the gland. Preferably,before tightening the gland in the outer pipe section, the length of thecoupling is adjusted as near as practicable to the length of theexisting gap or space between the pipe sections 10 and 11 so thatminimum movement of the inner pipe section 14 will be required inconnecting it with the section 11. The outer pipe section 13 isconnected by its threads 31 to the threads 32 of the upper pipe section10.

It will be apparent that any relative movement of the gland and the pipe14 during spacing-out requires that the gland be threaded away from theshoulder 14a. The grease in the annulus 28 aids in rotating the glandand pipe 14 relative to each other. When all connections are made, thegland 14 is then finally tightened by engagement of a wrench with theportion 24 of the gland. The gland is threaded farther into the lowerend portion of the pipe section 13 so that the mating tapered threads 20and 21 of the pipe section and gland, respectively, squeeze the glandradially inwardly, thereby increasing the pressure between the gland andthe inner pipe section 14 along the length of the mating straightthreads 22 and 23 on the gland and pipe section. A fluid-tight seal iseffected between the gland and the pipe section 14, leaving the pipesection, however, sufficiently free that it may be relatively easilyturned in the gland. For example, one test coupling loaded to 5,000pounds per square inch permitted rotation by the torque applied by handby a 24-inch pipe wrench. The pipe section 14 is then rotated in thegland to thread the lower end portion of the pipe section into the pipe11 by engagement of the threads 33 and 34 on the pipe sections 14 and11, respectively. The fact that the pipe section 14 is rotatable in thegland without affecting the fluid-tight integrity of the extensioncoupling permits the pipe section 14 to be threaded into the pipesection 1 1 to complete the interconnection of the pipe sections 10 and11 by the coupling. The design of the straight threads 22 and 23 and ofthe tapered threads 33 and 34 is such that the pipe section 14 isthreaded through the gland and into the pipe section 11 at the samerate. It will be apparent and may be preferred that the gland 24 may betightened after the connection of the coupling 12 between the pipesections 10 and 11 is completed, though it is to be understood that thenew and improved design of the coupling permits the gland to beinitially tightened to the extent necessary to prevent leakage whilestill allowing rotation of the pipe section 14 in the gland for purposesof accommodating the coupling to the required spacing between the pipesconnected together by the coupling. The length of the mating straightthreads in the gland and on the inner pipe section, together with theinward wedging effect of the gland around the straight threaded portionscaused by the outer tapered threads of the gland, along with otherfeatures, such as the finish of the threads on the inner pipe section inthe gland and the tolerance between the two straight threaded sections,prevents the fluid pressure within the couplings from forcing any fluidalong the straight threads out of the coupling, and thus preventsleakage. It will be evident that the sealing is accomplished by thecoupling without the need for the use of ring seals or gaskets betweenthe pipe sections of the coupling and the gland. Two spaced pipe endsare connectible together by the coupling without the need for rotationof either of the pipes being interconnected by the coupling. The onlylimitation on the distance which the coupling may be spaced out is thelength of the straight thread 23 on the inner pipe section 14.

A form of articulated pipe assembly 40 using the coupling concept ofFIGS. l-A and 1-H is illustrated in FIGS. 2-4. The assembly 40 isespecially adapted to connection of an underwater well head with fluidflow lines and well service lines which may extend horizontally,vertically, or at any intermediate angle with the well and well head.For example, the pipe assembly might be used to connect the well tofacilities at generally the same elevation as the well head and may beraisable, however, to provide access to the well from a locationgenerally vertically above the well head. A well head 41 is providedwith a connector body 42 to which is secured handling apparatus 43.Connected into the upper end of the body 42 are first ends of a largediameter inner flow line loop 44, an inner small diameter hydraulic lineloop 45, an outer large diameter flow line loop 50, and an outer smalldiameter hydraulic line 51. The other ends of the flow line and bydraulic line loops are connected with a first end of a middle couplinghaving a connector body 52 which is shown in enlarged detail in FIG. 4.Another set of flow and hydraulic line loops 44', 45, and 50', 51, areconnected at first ends into the other end of the middle connector body52. The other ends of the loops 44', 45, 50', and 51' are connected withanother middle connector body 52' which is identical in structure to thebody 52. Still another bundle of flow and hydraulic line loops may beconnected into the connector body 52', or, if conditions permit, theother end of the body 52' may be connected with flow lines 44" and 50"and hydraulic lines 45" and 51 which may either extend to wellfacilities at the surface or may extend to such facilities at or nearthe elevation of the well head, not shown.

As shown in FIGS. 3 and 4, the connector body 52 is a generallycylindrical member having separate longitudinal transverse borescorresponding in number and size to the hydraulic and flow line loopsconnected into the body. Referring to FIG. 4, the body 52 has a bore 53into which the hydraulic loops 51 and 51' connect and a bore 54 intowhich the flow line loops 44 and 44' connect by means of couplingsembodying the invention. The body 52 has end recesses 55 and 55' which,as represented in FIG. 3, encompass a sufficient portion of each end ofthe body to permit the flow line loops 44 and 44' to connect into thebody at a greater depth toward the longitudinal center line of the bodyso that the inner flow line loops may be of the same length as the outerflow line loops, thereby minimizing the number of parts of differentspecifications or sizes which are necessary for the complete articulatedassembly. Thus, by recessing the coupling body, as shown, the inner andouter flow line loops 44 and 50 may be of the same length and radius ofcurvature and thus are interchangeable.

The flow line loop 44 is connected into the bore 54 of the body 52 by agland 60 which corresponds in function to the gland shown in FIG, l-B.The end of the flow line loop 44 inserted into the body 52 is providedwith straight external threads 61 along a portion of the length of theend section of the loop inserted into the bore 54 of the body. The gland60 has straight internal threads which mate with the straight externalthreads 61 on the flow line loop. Externally, the gland60 is providedgland 60 tapered threads 63 which mate with tapered internal threads 64provided along an enlarged first end portion of the bore 54. The loop 44also has a smooth end portion 65 which extends into the body 52 inwardlyof the tapered threaded portion 64 of the bore. An O-ring seal 70 isfitted in an internal annular recess 71 of the body around the bore 54to seal with the end portion of the loop 44. The compressing effect ofthe tapered threads of the body 52 and the gland 60 squeeze the glandradially inwardly along the straight threaded connection between thegland and the flow loop 44. The length of the straight threadedconnection between the flow line loop and the gland acting under thepressure imposed along the threads by the tapered threads provides aseal along the straight threads while allowing the end portion of theflow line loop 44 threaded into the gland to rotate relative to thegland in the same manner as described in connection with the coupling12.

The end portion of the flow line loop 44' connected into the other endof the bore 54 of the body 52 is coupled with the body by identicalstructure referred to with the same reference numerals having a primemark added thereto. Inasmuch as the outer flow loops 50 and 50' areidentical to the inner flow line loops, the structure coupling the loopsinto the body 52 are identical and thus referred to by the samereference numerals as used in the above description. Similarly, theouter hydraulic line loop 51 is coupled into the bore 53 of the body 52by a gland 80 which has tapered external threads 81 and straightinternal threads 82. The external threads 81 mate with tapered internalthreads 83 of the body 52 around its bore 53. The internal straightthreads 82 of the gland mate with external straight threads 84 on theend portion of the hydraulic line loop. A smooth end portion 85 of theloop 51 inwardly of the straight threads 84 is inserted into the bodybore 53 inwardly of its tapered threaded region with a seal beingeffected around such portion by an O-ring 90 disposed within an annularrecess 91 of the body 52 around the bore 53. The outer hydraulic lineloop 51' connected into the other end of the bore 53 is held by thegland 80' and sealed with the body 52 by the O-ring seal 90'. The innerhydraulic lines 45 and 45' are connected into the bore 53' by the samegland and seal structure as used for the outer hydraulic line loops.

The structure of the well head body 42 into which the lower ends of thepipe loops 44, 45, 50, and 51 are connected and identical to one of theend portions of the body 52, and the pipe loops are connected into thebody 42 by the same coupling arrangement using the glands as shown anddescribed with respect to the body 52. Thus, the pipe loop bundleconnected into the well head body 42 is rotatable and twistable relativeto the well head body in the same manner as the pipe loops are withrespect to the body 52. The lower end of the well head body 42, notshown, is secured in any suitable manner into the well head 41 toconnect the flow passages of the body with flow passages through thewell head which lead to corresponding flow and hydraulic lines extendingdown into the well, not shown.

The structure of the connections of the various line loops into the body52 is identical to that shown and described with respect to the body 52so that the lines, both flow and hydraulic lines, connected into theseveral bodies of the assembly are all rotatable in the coupling bodiesby virtue of the straight threaded connections of the lines with theglands securing the lines into the bodies. The lines 44", and 51", shownin cross-section only in FIG. 2, may be another set of loop pipesections connected into still another coupling body identical to thebody 52 to provide added flexibility to the assembly 40. If the addedloop sections are not needed, the lines 44", 45", 50", and 51 may extendto well servicing, fluid storage and processing, and other suchfacilities at some remote location from the well head. These facilitiesmay be on land, on a platform in shallower water, in a submergedstation, or on a floating platform.

The coupling body 52 and the other such bodies in the pipe assembly havebeen shown with the end recesses and 55' so that both the inner andouter flow line loops may be made to the same specifications and thus beinterchangeable. Due to the large size of the flow line loops andconsequent difficulty of handling them on location, thisinterchangeability is particularly desirable. The coupling bodies arenot, however, provided with similar recesses for coupling the innerhydraulic line loops into the bodies, principally for the reason thatthe much smaller hydraulic line loopsare much more flexible and may bemore readily cut, threaded, and manipulated on the job than the largerflow line loops and, additionally, the provision of the added endrecesses in the coupling bodies for the inner hydraulic line loops wouldsubstantially increase the manufacturing cost of the coupling bodies. Itis to be understood, however, that such considerations do not eliminatethe use of such end recesses for the hydraulic line loops if they aredesired. If such additional recesses are formed or if the recesses 55and 55' are enlarged to encompass the area of connection of the innerhydraulic lines into the bodies, it then would be possible to provideinterchangeable inner and outer hydraulic line loops.

The assembly 40 is particularly flexible and thus may be moved through asubstantial arc at the end of the assembly defined by the body 52', andotherwise twisted and bent to a number of different desired shapes. Inthe configuration of the assembly represented in FIG. 2 the flow lines44" and 50" and hydraulic lines 45" and 51" turn horizontally toward theobserver. In the event that it is desired to raise the flow andhydraulic lines to vertical positions, they may be lifted, therebymoving the body 52' upwardly tending to twist the bundle of lines 44',45, 50, and 51' in a clockwise direction as viewed to the left of thereader toward the body 52. As the body 52 is raised, the resistance totwisting of the various lines will cause the ends of the lines securedby the glands into the body 52 to be rotated to some extent in the bodyas permitted by the straight threaded connections of the glands with thelines. Similarly, the lines will be twisted along their lengths betweenthe body 52' and the body 52. The body 52 will be rotated clockwise,transferring some twist to the lines 44, 45 and 50, 51. The extent towhich the lines are twisted and bent about their own longitudinal axeswill depend, of course, upon the flexibility of the material of whichthe lines are made, the thickness of the Walls forming the lines, andthe length of the lines. The body 52 is raised until it is in a verticalposition so that the lines 44", 45", 50", and 51" connected with it mayextend to the surface to a vessel or other facilities above the wellhead. The turning capability of the lines where they connect into thebodies 42, 52, and 52', together with the capacity of the lines to twistabout their own axes and about themselves, permits a great deal offlexibility in maneuvering the body 52 to a desired position relative tothe well head. As mentioned, additional sections may be included in theassembly by adding more flow and hydraulic line loops interconnected bycoupling bodies such as the body 52. The particular radius of curvatureof the flow and hydraulic line loops is selected to provide a flowpassage in each line capable of accommodating a string of pumpdown toolswith a minimum of resistance to tool movement along the curvature.Approximately a foot radius has been found to be quite satisfactory forthis purpose. After the assembly 40 has been raised and well servicingfrom above the well is completed, the assembly is readily returnable tothe condition shown in FIG. 2 for resumption of production.

The use of couplings embodying the invention in the pipe assembly 40 notonly provides a flow system having maximum flexibility with minimumconcern for sealing against leakage but also, quite importantly,provides a system wherein a minimum number of replacement spare partsare needed for the interchangeability of the inner and outer hydraulicand flow line loops, and minimum time and effort is required forreplacement of any one or more of the components due to the simplicityof the construction when using the glands for connecting the loops intothe coupling bodies. Additionally, the use of the new and improvedcoupling of the invention makes it possible to assemble and service anarticulated unit of the type shown without the need for additionalextension joints between the coupling bodies.

The loop bundles or sections of the pipe assembly 40 are especiallyuseful in making ocean floor completions in the drilling of subsea wellssuch, particularly, as oil wells. The assembly 40 permits well tubingstrings, the well head, and risers which are adapted to extend to thesurface to be run simultaneously by means of drill pipe connected withthe member 43. It will be apparent that the member 43 would be equippedwith a suitable connection for support from a string of drill pipe.After so running this equipment, pressureand production tests, ifdesired, are made and the risers are buoyed off for later pick up by apipe laying barge. As the barge moves off, the lines are then easilylaid down. These various maneuvers are readily accomplished due to theflexibility of the connection between the risers and the well head madethrough the articulated pipe assembly 40. Since the assembly permitsvertical and horizontal connection and is adjustable over the rangebetween such connections, the risers are readily laid down and liftedbetween vertical extension to the surface and horizontal extension alongthe ocean bottom. After these maneuvers are performed with the pipeassembly and the lines are laid down for production and well servicingand other procedures to be accomplished through the line, the couplingglands such as 60, 60', and 80' may be further tightened by either adiver or a suitable submarine system for engaging and manipulating thefunctional parts of the pipe assembly.

Referring now to FIGS. 5-8, another articulated pipe assembly 100 isillustrated for such uses as making well head connections similar tothat of the assembly 40 in FIG. 2. The assembly includes a plurality ofinterconnected identical flanged pipe end sections 101, glands 102, pipecollar sections 103, and subor pinpipe sections 104. In FIG. 7, the pipeassembly is shown in one preferred assembly arrangement which provides aflow line turn, while FIG. 8 represents an important functional featureof the pipe assembly which is the capability of being straightened toprovide a substantially straight flow line. One especially important useof the flow line assembly is the same as that previously discussed forthe assembly 40 which is the use of the assembly on a well head which,during one stage of operation, is connected with facilities whichrequire a generally horizontal flow line connection to the well headwhile capability of vertical entry into the well head is desired forservicing purposes. The articulated assembly 100, as illustrated, isconnected at opposite ends to identical flow line flanged pipe sections105, one of which may be connected into a well head or any desired linewhile the other is connected with a flow line leading to fluid storage,well servicing, and other required facilities, not shown.

Specific details of the component parts of the articulated pipe assemblyare illustrated in FIGS. 5 and 6. Referring to FIG. 5 the flangedsection 101 has an end flange 110 provided with circumferentially spacedbolt holes Ill to receive bolts 112 which secure the flange to theflanged end of the flow line section 105. A gasket l13 is disposed incooperating end recesses in the flanges 110 and the flange on the pipesection for sealing around the bore through the flanged coupling toprevent leakage between the flanges. The flange section 101 has a bodyportion 114 provided with a bent or angularly disposed externallythreaded end portion 115. The axis of the end portion 115 extends at aslight angle to the axis of the central body portion of the body 115,the degree of which depends upon the total number of sections of collarand subportions included in the complete assembly 100 and the totaldegree of curvature traversed by the complete assembly. In theparticular design of the assembly 100 the axis of the threaded endportion 1 15 lies at an angle of )4; with the axis of the main bodyportion 1 14 of the flanged section 101. The end portion 115 hasexternal straight threads 120 which are cut on the end portion on acenter line or axis which is coincident with the angularly disposed axisof the end portion 115. The body 114 has a bore 121 which is ofirregular configuration having a somewhat out-of-round cross-section tomore readily accommodate a train of pumpdown tools as it traverses thecurved bore defined by the assembly of parts comprising the articulatedpipe assembly 100. This irregular bore configuration is achieved byforming the lower half 121a, or 180 of the bore along the lower half ofthe body, as shown in FIG. 5, with a cylindrical surface formed on astraight longitudinal axis of the body 114. The upper half surfaceportion l2lb of the bore, as shown in FIG. 5, is a longitudinally curvedsurface, half-circular in cross-section, developed relative to a curvedlongitudinal axis line having a radius equal to the radius of curvatureof the total assembly 100, as viewed in FIG. 7, when it is in its curvedconfiguration. Thus, the surface 121b is generated along an axis whichextends near the center line of the bore 121, such axis being formed ona 5 foot radius so that the total assembled curvature of the assembly100 is arranged along a 5 foot radius to facilitate the movement ofpumpdown tools through the pipe assembly. To aid in better understandingthe development of the surfaces 121a and l2lb defining the bore 121,axis lines are illustrated along the bore and about which the twosurfaces are developed. The cylindrical surface 121a is thus developedalong the longitudinal axis l2laa, while the non-cylindrical upper boresurface l2lb is developed along the curved longitudinal axis 121bb whichhas a radius R which, in the particular preferred design for standardpumpdown practice, is approximately 5 feet. The previously discussedaxis 115a of the end section 115 is aligned at the 5 5%" angle with theaxis 12laa.

The gland 102 has a tool-engaging extension portion 130 for securing awrench or similar tool to the gland and a threaded portion 131 whichfunctions to connect the collar section 103 to the flange section 101.The gland portion 131 has straight internal threads 132 which mate withthe straight external threads 120 on the end portion 115 of the pipesection 101. The section 131 also has tapered external threads whichgenerally taper inwardly toward the end of the gland for engagementwithin the pipe collar section 103. The collar section 103 has an endportion 140 provided with tapered internal threads 141 which mate withthe tapered external threads 133 of the gland for securing the gland inthe end portion of the collar section. When the gland is tightened tothe proper degree in the collar section end portion, the tapered threadsof the collar section and the gland supply the required inwardlysqueezing force to the gland to hold the straight threaded connectionbetween the gland and the end portion 115 of the pipe section 101 in asealed, yet rotatable, relationship. Thus, when properly securedtogether, the straight thread connection between the gland and the pipesection 101 permits the gland and the pipe section 103 to rotate on andrelative to the pipe section 101 without affecting the fluid tightnessof the coupling of the pipe assembly.

The pipe collar section 103 has a central body portion 142 extending amajor portion of its length and is provided with an internally threadedend portion and an identical internally threaded opposite end portion143. The end portion 143 has internal tapered threads 144. The axis ofeach of the end portions 140 and 143 of the pipe section 103 lies at aslight angle with the principal axis of the main body portion 142 of thepipe section. In this particular design this angle is 5 which, aspreviously stated, is the same angle of alignment of the end section 115with its main body portion 114 of the pipe section 101. The netcumulative effect of the angular position of the adjoining pipe endportions 115 and 140, since they each lie at an angle of 5 to the axisof the main body portion of the members of which they are a part, is toposition the pipe sections 101 and 103 at an angle of l 1 with respectto each other when the pipe sections are at the maximum angle withrespect to each other, as shown in FIG. 5, at their fully turnedrelative positions.

Thus, since each of the end portions of the pipe section 103 lie at anangle of 5 to the central axis of the pipe section, the pipe sectionprovides a total turn of 1 1 141 when functioning in the assembly 100.The bore of the pipe section 103 has an irregular shape of the same typeas the bore 121 in the pipe section 101. The lower half surface 145a ofthe bore at the position of the pipe section of FIG. 5 encompassingsubstantially the lower 180 degrees of the bore is a cylindrical surfacegenerated about an axis which comprises a longitudinal axis of the mainbody portion 142 of the pipe section. The upper half of the bore surfacecomprising the upper 180 of the bore, as viewed in FIG. 5, is a curvedsurface 145b, semicircular in cross-section, and generated along alongitudinal axis of the same radius and from the same center as theradius R for the surface l21b of the pipe section 101 to facilitate themovement of a train of pumpdown tools through the pipe assembly 100.

A subor pinpipe section 104 is connected by another gland 102 to thepipe section 103. The pipe section 104 is structurally and dimensionallyvery similar to the flanged pipe section 101 except that the section 104has identical angularly disposed opposite end portions 150, each ofwhich is externally threaded with straight threads to engage a gland102. Referring specifically to FIG. 5, the pipe section 104 has an endsection provided with straight external threads 151 which mate with theinternal straight threads 132 of the gland 102. The end section 150 ofthe pipe section 104 is formed on an axis at an angle which, in thisparticular design, lies at 5 with the principal axis of the pipesection, such axis being the axis of the central main body portion 152of the pipe section 104. The opposite end of the pipe section 104, notshown, has an identical angularly disposed end portion 150 externallythreaded with straight threads which will mate with the internalstraight threads of another of the glands 102. The bore 153 through thepipe section 104 is of irregular shape having a lower cylindricalsurface section 1530 encompassing substantially degrees of the length ofthe pipe section as viewed in FIG. 5. The upper 180,

as seen in FIG. 5, of the bore 153 has a surface 153b which issemicircular in cross-section and longitudinally formed on a radius Rcorresponding to the radius of the curved total assembly 100 which, inthe particular design shown, is approximately feet. Thus, the pipesection 104 readily accommodates a moving pumpdown tool train andprovides a turn of 11 1Q as is provided by the other pipe sections. Thepipe section 104 is rotatable in the gland 102 along the straight lineconnection relative to the gland and the pipe section 103 withoutaffecting the fluid-tightness of the coupling between the pipe sections103 and 104 as previously discussed.

The number of pipe sections 103 and 104 connected between the endflanged sections 101 at the opposite ends of theassembly 100 aresufficient to provide a 90 turn in the articulated loop formed bythepipe sections between the flanged end sections. Referring to FIG. 7,viewing each coupling or joint at each of the glands 102 as providing 11/z-turn, the total turn of the loop formed by the assembly inthepositions shown in FIG. 7 traverses 90. Since each of the joints iscomprised of two angularly positioned end portions of pipe sections,each set at 5 to the principal axis of the pipe section, the total turnprovided at the joint is 11 1%. Since there are eight such joints in theassembly 100, it will be apparent that the total cumulative turnprovided by the joints is 90.

Each joint at each gland 102 in the assembly 100 has the capability ofrotation without affecting the fluid tightness of the pipe assemblywithin, of course, practical limits of disconnection of the joint byunscrewing the gland from the pin portion of the pipe to which it isthreaded and, within that extreme limitation, unscrewing of the gland tothe extent that the fluid-tight integrity of the joint is affected. Solong as these extremes are not exceeded and sufficient straight threadcontact is maintained to keep the joint fluid tight, the connected pipesections may be rotated, one relative to the other. Referringspecifically to FIGS. 5 and 6, each joint may be rotated 180 toeffectively straighten the connecting pipe sections. Since each pipesection has an end portion set at an identical angle to the other,rotation of one pipe section relative to the other effectively cancelsthe degree of turn at the joint to thus straighten one pipesectionrelative to the other. For example, referring to FIG. 5, rotationof the pipe section 103 relative to the pipe section 101, therebyturning the pipe section 103 and its associated gland 102 through 180,effectively cancels the turn at the joint between the pipe sections sothat the two sections are thereby rendered straight as shown in FIG. 6.In FIG. 5 the angularity of the end portion 115 on the pipe section 101and thatof the end portion 140 on the pipe section 103 is downwardly inboth instances. In contrast, in FIG. 6 the angularity of the end portion115 of the pipe section 101 is still downwardly while the angularity ofthe end portion 140 of the pipe section 103 is upwardly so that it willbe seen that the net result is straightening of the joint. The pipesection 104 is then revolved in its gland 102 I80", thereby cancellingthe cumulative turn provided at the joint between the pipe sections 104and 103 to straighten such joint. Thus, the rotation of each pipe jointrelative to the adjacent pipe joint to which it is connected through 180straightens the relationship between the adjoined pipe joints. The pipejoints may be rotated in either direction so long as a full 180 istraversed. The cumulative effect of 180 rotation of each of the pipejoints in the assembly 100 produces an effectively straight pipeassembly as shown in FIG. 8. Alternative direction of rotation of thejoints may be employed so that at either end of the assembly it shouldnever be necessary to revolve either of the flanged flow lin'e sections105 more than 180.

For example, the flanged end section 101, shown in FIG. 5, may berotated toward the observer 180, thereby straightening the section 101relative to the section 103 and the gland I02 joining the section 103 tothe section 101. Then, the sections 101 and 103, along with the gland102 joining the section 104 to the section 103, may be revolved as aunit 180 back toward the observer, thereby straightening the section103' relative to the section 104; and since a straight relationshipalready exists between the sections 101 and 103, the three sections,101, 103, and 104, now are straight as seen in FIG. 6. Next, the threesections may be revolved as a unit 180 to provide a straightrelationship with the fourth pipe section. This sequence of 180revolution of the straightened segments of the assembly 100 is continueduntil the whole assembly is straight and vertically aligned as shown inFIG. 8. Also, it will be recognized that if each section 103 is revolved180 from the relative postions of FIG. 7, the entire assembly isstraightened to the configuration of FIG. 8 without rotation of eitherend flange 110.

Thus, the assembly 100 provides a mechanism whereby a well may beconnected to a flow line running along or near the ocean bottom tohorizontally spaced well facilities, and when it is desired to gainvertical access to the well for various well servicing procedures whichmight require direct straight access in through the well head, thearticulated coupling 100 may be lifted and alternately revolved until itis straightened to the shape of FIG. 8, such straightening beingaccomplished without affecting the fluid tightness of the pipe assembly.

It will be evident that the use of the coupling concept described andillustrated in FIGS. l-A and l-B permits the new and novel structure ofFIGS. 7 and 8. If the line 105 is sufficiently flexible running from thewell head articulated coupling, the straightening procedure may beaccomplished without disconnection of the line since no more than 180rotation is ever required to effect the straightening.

In addition to providing an articulated structure which may bemanipulated between straight and curved shapes, the pipe assembly 100also provides an adjustable flow coupling assembly for the connection ofspaced flanges which are disposed along different axes. For example,referring to FIG. 7, presuming the flanges 105 are fixed as shown toimmovable pipes aligned at angles with each other. An assembly has theadjustable capability of connection of the two spaced flanges byrotation of the pipe sections making up the assembly sufficiently toaccommodate it to the spacing of the flanges. It will be apparent thatinitially an assembly 100 must be selected which approximately fits thespacing between the flanges. The assembly may then be connected at oneend leaving the other end free for adjustment to accommodate theassembly to the end flange 105 spacing. If the lower pipe section 101 isconnected with the lower flange 105 and the upper flange on the upperpipe section 101 is slightly above or below the flange 105, the positionof the flange 110 may be altered by rotating the adjacent pipe section103 a full 360 in either direction to effectively lengthen or shortenassembly 100 as needed. Similarly, if the flange 110 is displaced withrespect to the flange 105 such that the flange 110 requires movementinwardly or outwardly relative to the flange 105, rotation of one ormore of the pipe sections 103 a full 360 may be employed to make thenecessary adjustment in the assembly 100 for coupling its upper flange110 to the flange 105. Thus, any one or more of the pipe sections 110may be rotated a full 260 at least one or two turns for effectivelyshortening or lengthening the pipe assembly and also changing theeffective radius of the assembly. These adjustments may be made so longas no one of the threaded connections is rotated sufficiently tojeopardize the tightness of the connection or affect the seal integrityof the coupling. Thus these adjustments may be made within limits whichretain metal-to-metal seal integrity. The adjustability of the assembly100 is particularly important where use in a confined submarine wellheadcellar or in an ocean floor environment is desired. These adjustmentsmay be made with a small wrench and thus permit the articulated pipeassembly to be accommodated to variation in length and radiusrequirements by use of tools which can be manipulated in confined spacesor under adverse conditions such as when being operated by divers orsubmarine equipment.

Referring to FIG. 9, an alternate form of coupling gland 160 isillustrated for use in such applications as the articulated pipeassembly of FIGS. -8 in lieu of the gland 102 to produce a greaterstress concentration along a portion of the rotatable straight threadconnection. The gland 160 also represents a design concept which may beapplied to the gland 15 for effecting an increase in stressconcentration along the straight threaded connection. The gland 160 hasa threaded coupling portion 161 and an extension 162 provided with aplurality of flat side faces 163 for engagement of a suitable tool, suchas a wrench, for rotating the gland. The threaded portion 161 includesinternal straight threads 164 adapted to engage similar externalstraight threads, such as the threads 131 on the end portion of the pipesections 101 of the pipe assembly 100. Externally, the gland portion 161has threads formed at two angles or degrees of taper. The threads 165extending from a line 170 to a line 171 are straight threads or threadsof slight taper while the threads 172 extending from the line 171 to theend 173 of the gland are of a much move severe or higher angle of taper.The threads 172 produce a higher stress concentration along that portionof the gland on which the threads are formed than exists along the otherthreaded portions of the gland so that a correspondingly higher stressconcentration is effected along the threads 164 which are alignedlongitudinally with the threads 172 on the gland, thus causing a tightersealing relationship along the joint between the threads 164 and thestraight threads of the pipe member on which the gland 160 is threaded.The gland 160 otherwise functions identically to the gland 102 and isused just in those instances where the higher stress concentration isdesired for improved sealing along a coupling.

FIG. illustrates a coupling 180 embodying the invention which includes agland 181 to connect tubular members 182 and 183. The coupling 180 isparticularly useful in situations where the structure of the member 182does not permit it to be readily engaged by a tool, such as a wrench,while the gland 181 can be held against rotation while the member 183 isrotated by a wrench or other suitable means. One such arrangement wherethese conditions might exist is in the case of the member 182 being anexternally smooth, highly polished tube having no surfaces engageable bya wrench. The gland 181 has a threaded portion 184 and an extensionportion 185 having an external surface which is adapted to be engaged bya wrench or other similar tool. The threaded gland section 184 hasinternal inwardly tapered threads 191 and external, more steeply taperedthreads 192. The internal threads 191 engage similarly tapered threads193 on the member 182. The external gland threads 192 engage internaltapered threads 194 within the member 183. The steeper taper of theexternal threads on the gland permits a seal to be effected along theinternal threads of the gland with the member 182 without the necessityof applying high torque between the gland and the member 182. Forexample, the gland 181 is threaded on the member 182 and tightenedlightly to the extent that torque can be applied to the gland withoutthe need of using a wrench on the member 182. In so doing, the internalthreads 191 of the gland are fully engaged with the external threads 193of the member 182 without, however, any severe tightening of the glandon the member 182. The member 182 is then threaded on the gland byengagement of the internal threads 194 with the external gland threads192. One wrench is then engaged with the gland to hold it againstrotation while another wrench is engaged with the member 183 forrotating the member relative to the gland. The steeper taper of thethreaded engagement between the external threads of the gland and theinternal threads of the member 183, when torque is applied to the member183, increases the stresses in the threaded portion of the glandradially inwardly to effectively tighten the internal threadedconnection of the gland with the member 182, thereby effecting a sealalong the connection between the threads 191 and 193. The gland iseffectively tightened on the member 182 by virtue of the steeper threadconnection between the gland and the member 183 as compared with thethread connection between the gland and the member 182.

FIG. 1 1 illustrates a still further form of tubular member coupling 200which is used to achieve a sealed threaded joint between two tubularmembers after the members have been aligned at desired positionsrelative to each other. The coupling includes a gland 201 whichinterconnects a first tubular member 202 with a second tubular member203. A further tubular member 204 is illustrated disposed through themember 203, such member, however, comprising no part of the coupling200. The gland 201 has internally and externally threaded portion 205and an extension portion 210 having a plurality of flat faces 211 topermit the engagement of a wrench for rotation of the gland. Thethreaded gland portion 210 has external straight threads 212 which meshwith internal straight threads 213 in the member 202. The threaded glandportion 210 also has internal tapered threads 214 which mesh withexternal tapered threads 215 on the tubular member 203. The internalgland threads 214 taper from a maximum diameter at the extension 210 toa minimum diameter at the end 215a of the gland so that the end 215a isthicker than the threaded gland portion adjoining the extension2l0.Similarly, the taper of the exter nal threads 215 on the member 203 isfrom a minimum diameter at the end 210a to a maximum diameter at thebase end of the threads 21%. Stated otherwise, the threads 212 and 214are diverging at the end 215a of the gland.

A primary objective of the coupling design 200 is the capability to betightened without affecting a preset alignment between the members 202and 203. Thus, in one procedure of assembly of the coupling, the tubularmembers 202 and 203 are threadedly interconnected with the gland 201,and the three members are threaded together until the desired relativepositioning is achieved between the members 202 and 203. For example,such positioning may comprise the longitudinal spacing of given featuresor marks on the tube members at a predetermined distance from eachother. With the two members coupled by the gland aligned as desired, themembers are both held against rotation while the gland is engaged by awrench contacting the surfaces 211 and rotated in a direction, dependingupon whether rightor left-hand threads are employed, which threads thegland farther on the member 203, thereby more tightly engaging themating threads 214 and 215. The tapered threaded connection between thegland and the member 203 stresses the gland radially outwardly, therebytightening the straight threaded connection comprising the threads 212and 213 between the gland and the tubular member 202. The gland istorqued to a predetermined value, such as to about 1,200 foot pounds, toobtain the desired tightness between the gland and the tubular membersfor achieving an effective seal along the tapered and straight threadedconnections. If desired, the gland and tubular members are weldedcircumferentially at 220 and 221. Thus, the coupling 200 permitsinterconnection of tubular members at desired relative positions and atightening of the threaded connections with the members to a desiredvalue without affecting the relative preset positions of the members.The structure of the coupling of FIG. 11 additionally permits assemblyand testing and subsequent removal of the inner member 203 to permitwelding at 221 with the internal members removed, if such internalmembers are heat sensitive. Later welding at 220 may then beaccomplished at a distance farther from internal heat sensitivecomponents which may be affected by the weld at 221.

It will be evident that other combinations of pipe sections andfluid-tight rotatable couplings may be used to form articulated pipeassemblies capable of assuming various desired shapes and capable ofbeing shifted to such shapes while retaining fluid tightness. Thechanging of the degree of angularity of theend portions of the pipesections may provide other desired changes in the total angle of turn atany one of the joints.

What is claimed and desired to be secured by Letters Patent is: i

'1. A coupling for providing a connection between first and secondthreaded members comprising: a first member having a portion providedwith straight external threads; a second member having a portionprovided with tapered internal threads; a coupling member between saidfirst and second members, said coupling member having straight internalthreads mating with said straight threads on said first member and saidcoupling member having tapered external threads mating with said taperedinternal threads in said second member; the threaded connection betweensaid coupling member and said first member and the threaded connectionbetween said coupling member and said second member being disposedlongitudinally in concentric overlapping relationship; the threadedconnection between said coupling member and said second member effectinga radial stress on said coupling member providing a sealing force alongthe threaded connection between said coupling member and said firstmember; the finish of said coupling member and said first member alongthe straight threaded connection between said coupling member and saidfirst member and the tolerance between said straight threads of saidcoupling member and said first member being related to and the length ofsuch threaded connection being proportional to the operating pressure offluid within said coupling to permit said first member to behand-rotated in said coupling member while maintaining a fluid-typeconnection at said coupling member along said straight threadedconnection between said coupling member and said first member underoperating pressure; said coupling member being provided with anextension portion projecting beyond said overlapping portions of saidfirst and second members for engagement of a tool on said couplingmember for rotating said coupling member for loosening, tightening, andadjusting the effective length of said coupling; said extension portionof said coupling member having a smooth internal bore portion disposedbetween the outward end of the internal threads along said couplingmember and the free end portion of said coupling member providing agrease annulus for receiving grease to lubricate said straight threadedconnection between said coupling member and said first member; saidcoupling member having a grease-fitting opening communicating with saidgrease annulus for injection of grease into said annulus; and saidcoupling member having internal threads along said free end portion toseal the outward end of said annulus and to provide structural supportfor said free end portion of said coupling member along said firstmember.

2. A pipe coupling for connecting two pipes to provide a sealedrotatable joint between said pipes comprising: a first inner pipesection having a portion thereof provided with external straightthreads; a second outer pipe section having a portion thereof providedwith internal tapered threads; a coupling gland for interconnecting saidfirst and second pipe secions, said coupling gland having internalstraight threads formed to mate with said straight threads on said innerpipe secton, said coupling gland having external tapered threads to matewith said internal tapered threads in said outer pipe section; saidtapered threads of said gland and said outer pipe section being sorelated to effect radially inwardly squeezing action on said gland assaid gland is threaded into said outer pipe section; said straightthreads within said gland and around said inner pipe secton mating alonga length proportional to the operating pressure within said pipecoupling to effect a fluid seal'between said gland and said inner pipesection to seal against said operating fluid pressure within saidcoupling when said coupling gland is squeezed by said action of saidtapered threads on said coupling gland and within said outer pipesection, said inner pipe section being hand rotatable in said couplingwhile maintaining said fluid seal for adjusting the effective length ofsaid coupling under said section within said gland, said gland having agrease fitting opening to permit injection of grease into said annulargrease chamber; and said gland having internal threads along said freeend portion for closing the outward end of said grease chamber and forsupporting the free end of said gland on said straight external threadsof said inner pipe section.

1. A coupling for providing a connection between first and secondthreaded members comprising: a first member having a portion providedwith straight external threads; a second member having a portionprovided with tapered internal threads; a coupling member between saidfirst and second members, said coupling member having straight internalthreads mating with said straight threads on said first member and saidcoupling member having tapered external threads mating with said taperedinternal threads in said second member; the threaded connection betweensaid coupling member and said first member and the threaded connectionbetween said coupling member and said second member being disposedlongitudinally in conCentric overlapping relationship; the threadedconnection between said coupling member and said second member effectinga radial stress on said coupling member providing a sealing force alongthe threaded connection between said coupling member and said firstmember; the finish of said coupling member and said first member alongthe straight threaded connection between said coupling member and saidfirst member and the tolerance between said straight threads of saidcoupling member and said first member being related to and the length ofsuch threaded connection being proportional to the operating pressure offluid within said coupling to permit said first member to behand-rotated in said coupling member while maintaining a fluid-typeconnection at said coupling member along said straight threadedconnection between said coupling member and said first member underoperating pressure; said coupling member being provided with anextension portion projecting beyond said overlapping portions of saidfirst and second members for engagement of a tool on said couplingmember for rotating said coupling member for loosening, tightening, andadjusting the effective length of said coupling; said extension portionof said coupling member having a smooth internal bore portion disposedbetween the outward end of the internal threads along said couplingmember and the free end portion of said coupling member providing agrease annulus for receiving grease to lubricate said straight threadedconnection between said coupling member and said first member; saidcoupling member having a grease-fitting opening communicating with saidgrease annulus for injection of grease into said annulus; and saidcoupling member having internal threads along said free end portion toseal the outward end of said annulus and to provide structural supportfor said free end portion of said coupling member along said firstmember.
 2. A pipe coupling for connecting two pipes to provide a sealedrotatable joint between said pipes comprising: a first inner pipesection having a portion thereof provided with external straightthreads; a second outer pipe section having a portion thereof providedwith internal tapered threads; a coupling gland for interconnecting saidfirst and second pipe secions, said coupling gland having internalstraight threads formed to mate with said straight threads on said innerpipe secton, said coupling gland having external tapered threads to matewith said internal tapered threads in said outer pipe section; saidtapered threads of said gland and said outer pipe section being sorelated to effect radially inwardly squeezing action on said gland assaid gland is threaded into said outer pipe section; said straightthreads within said gland and around said inner pipe secton mating alonga length proportional to the operating pressure within said pipecoupling to effect a fluid seal between said gland and said inner pipesection to seal against said operating fluid pressure within saidcoupling when said coupling gland is squeezed by said action of saidtapered threads on said coupling gland and within said outer pipesection, said inner pipe section being hand rotatable in said couplingwhile maintaining said fluid seal for adjusting the effective length ofsaid coupling under said operating fluid pressure; said coupling glandhaving an extension portion projecting from within said outer pipesection along the external threaded portion of said inner pipe section,said extension portion being provided with a smooth internal boreportion spaced from the outer free end portion of said gland to providean annular grease chamber around said straight threads on said innerpipe section to contain grease for lubricating said inner pipe sectionfor rotation of said inner pipe section within said gland, said glandhaving a grease fitting opening to permit injection of grease into saidannular grease chamber; and said gland having internal threads alongsaid free end portion for closing the outward end oF said grease chamberand for supporting the free end of said gland on said straight externalthreads of said inner pipe section.